This invention relates to a multiple cylinder Stirling engine and particularly to one that has multiple gas combustors which act as heat sources for the engine which are integrated into the structure of the engine.
Stirling cycle engines may be powered directly by a source of heat such as from solar energy sources, combusted gas, etc. The output mechanical energy of the engine can be used to do direct work or for the generation of electrical energy, etc. In some applications, it is desirable to use flue gases from a combustible fuel to provide the heat input energy for the engine. In one type of prior art Stirling engine, a combustion apparatus remote from the engine is used in which the heat energy is transferred through a heat transport mechanism such as a liquid metal heat pipe. Although such devices perform very satisfactorily and do offer thermodynamic benefits, they constitute, however, a large proportion of the heat capacity of the heating system which requires a considerable warm-up time. For some applications, this is not desirable. Moreover, the requirement of providing a heat pipe adds to the complexity and packaging size of the total system.
Other types of prior art Stirling engines incorporate one large gas combustor in combination with an integrated heater head of a number of working cylinders. Such heater heads are not very suitable for volume production due to the complexity and long brazing time of the tubes in the massive heater heads. Other prior art Stirling engines with integrated combustors have efficiency disadvantages due to the configuration of combustor and the heat transfer surfaces of the engine heat exchanger.
This invention is directed toward a Stirling engine with multiple gas combustors that are integrated into the structure of the engine to provide a compact and efficient energy conversion machine. The system eliminates the requirement of a separate heat pipe for transferring heat from a remote source. Individual combustion chambers are provided for each of the cylinders of a multiple cylinder Stirling engine. The relatively small size of the combustion chamber allows the heat exchanger for each cylinder to be constructed of a circular bundle of tubes terminating in a circular manifold. The manifold is connected to the cylinder by one or more hot connecting ducts.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.